Health Behaviour Change in Weight Management for People With Higher Weight and Symptoms of Common Mental Health Problems: A Qualitative Study.

Service users and healthcare professionals described five themes capturing how adults with higher weight and symptoms of common mental health problems experience health behaviour change in Tier 2 weight management services.

• Themes: (1) The emotional weight of change, (2) Health on the margins of daily life, (3) Connection and judgement shape the journey, (4) Treating the whole person, and (5) Self-care as a foundation for lifelong change.
• Semi-structured interviews were conducted with service users (n = 11) and healthcare professionals (n = 11) recruited from UK T2WMS.
• Analysis used codebook thematic analysis within a critical realist frame, with deductive mapping to the COM-B model and Theoretical Domains Framework (TDF).
• The themes reflected a dynamic interplay of emotional, social and structural factors.

Barriers to health behaviour change included emotional fluctuation, stigma, low self-efficacy, relational pressures and structural constraints.

• Barriers were identified across eating behaviours, physical activity, emotion regulation and self-regulation behaviours.
• Findings drew on both service user and practitioner perspectives.
• The themes 'The emotional weight of change' and 'Health on the margins of daily life' relate to these emotional and structural barriers.

Facilitators of health behaviour change included self-compassion, emotional regulation, small achievable goals, inclusive groups and supportive practitioner relationships.

• Facilitators were identified across eating, physical activity, emotion regulation and self-regulation behaviours.
• The themes 'Connection and judgement shape the journey' and 'Self-care as a foundation for lifelong change' relate to these facilitators.
• Facilitators were mapped to COM-B/TDF domains.

Provision that centres weight loss as the primary measure of success and is delivered in a standardised format was poorly aligned with the needs of people with symptoms of common mental health problems.

• Tier 2 Weight Management Services in the UK emphasise diet and physical activity with limited psychological input.
• The theme 'Treating the whole person' reflects the need for provision that addresses more than weight.

The authors suggest that embedding trauma sensitivity, relational safety, flexible pacing and broader outcome measures may better support sustained engagement.

• Mapping to COM-B/TDF and Behaviour Change Wheel intervention functions offers a psychologically informed framework to guide commissioners and practitioners.
• This is presented as an implication of the qualitative findings, not as a tested intervention.

Patient and public involvement shaped the study's design and terminology.

• An advisory group of four members (two with lived experience of higher weight and symptoms of CMHPs, two healthcare professionals delivering T2WMS) contributed to study design, recruitment materials and interview guides.
• The group shaped the study's non-stigmatising terminology.
• All participants were invited to review preliminary findings, which informed refinements to thematic language.
• PPI was documented using the GRIPP2 short-form framework.